A virtual image display apparatus (display apparatus) to make an observer observe a two-dimensional image, which is formed by an image forming apparatus, as an enlarged virtual image with a virtual image optical system has been known, for example, from JP 5-134208 A.
In the virtual image display apparatus disclosed in JP 5-134208 A, a liquid crystal display unit is illuminated by light from a light source which light is collimated by a lens through a polarizing plate and image light of the illuminated liquid crystal display unit is collected at a first focal point by a lens group. Then, the collected light is reflected by a concave mirror, is collected at a second focal point on a front surface of the lens of a pupil through the polarizing plate, and reaches a retina. Accordingly, it is possible for a user to observe an image.
Also, the following head mounted display has been known, for example, from FIG. 6 in JP 10-206786 A. That is, a half mirror and a concave mirror are provided in a front position of a right eye of an observer, a concave mirror formed as a concave-shape with respect to the half mirror and the observer is provided in a front position of a left eye of the observer, and in an upper position of the half mirror, an image display panel (image forming apparatus) is arranged.